Electric-arc light



(No Model.) 3 Sheets-Sheet 1.

G. J. MURDOOK.

ELEGTRIU ARC LIGHT.

N0. 275,510. Patented Apr. 10,1883.

N. PETERS. PhnIo-Likhuglaphcr. mammal. D. cv

(No Model.) 3 Sheets-Sheet 2. G. J. MURDOOK.

ELECTRIC ARC LIGHT.

N0. 275,510. Patented Apr. 10,1883.

Mum/717,7

(No Model.) 3 Sheets-Sheet 3.

G. J. MURDOOK.

ELEOTRIO ARC LIGHT.

Patented Apr. 10,1883.

mmfiiaf. g m/m5 wry.

UNITED STATES PATENT OFFICE.

GEORGE J. Mun-noon, or BING-HAMTON, NEW roan.

ELECTRIC-ARC LIGHT.

SPECIFICATION forming part of Letters Patent No. 275,510, dated April 10, 1883,

(No modehl To all whom it may concern:

Be it known that I, G. J. MURDocK, of Binghamton, in the county of Broome and State of New York, have invented certain new and useful Improvements in Electric Lights; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it pertains to make and use the same.

My invention relates to are electric lamps of the class in which the separation and feeding of the carbons are effected by electromagnetic devices, the operation of the feed depending upon the variation of resistance at the voltaic arc.

Theobjectofmyinventionistoprovidean arclamp with a simple, reliable, and highly-sensitive carbon separating and feeding mechan ism.

My invention consists in certain novel constructions and combinations of devices, which will be hereinafter fully described, and pointed out in the claims.

In the accompanying drawings, Figure 1 is a front elevation of an electric lamp constructed according to my invention. Fig. 2 is an enlarged vertical central section of an intermediate portion of the lamp between its base and top, and including the electromagnetic carbon-controlling mechanism, the section be ing taken in a plane parallel with the plane of projection in Fig. 1. Fig. 3 is an enlarged horizontal section on the linexa: of Fig. 1. Fig. 4 is a similar section on line g yof Fig. 1. Fig. 5 is an enlarged detached perspective view of the lifting-clutch. Fig. 6 is an enlarged section, line 2 z of Fig. 1.

Referring to Fig. 1, the letter A indicates the lamp-base, which is made of wood or other non-conducting material, and provided with the binding-posts p a for connecting the lamp in circuit.

B is the metallic holder of the lower carbon, C, the base I) of this holder being secured to the lamp-base, and having secured to it the metallic standards D and D, which support the superstructure of the lamp. The upper ends of the standards D and D terminate in elbows d (1, made of vulcanite or other strong non-conducting material, and to these elbows are secured the lower ends of two vertical metallie bars, E and E, preferably rectangular in cross-section, and connected at their tops by a vulcanite bridle, 0.

The letter F designates the electro-magnet which controls the movement of the upper carbon, C. The core G of the magnetis tubular (see Fig. 2) and surrounded by a coil, f, formed of three or more layers of stout insulated copper wire, which will offer but little resistance to the electric current. The heads/"f of the coilfare made of insulating material, preferably vulcanite, and have a considerably greater diameter than the coil, so that apertures formed in their margins may embrace the vertical metallic bars E E, which form supporting-guides upon which the magnet may be adjusted ertically, being held in place by clamping-screws h h, which pass radially through the margin of the lower head, and may be adjusted to bind upon the vertical bars.

Through the bore of the tubular core G is arranged loosely a metallic tube, I, the outer surface of which is heavily copper-plated to prevent its adhering to the core when thelatter is magnetized. The lower end of the tube I is closed and secured to the upper-carbon holder 13, which is provided with a flange, b, for a purpose which will be hereinafter eX- plained.

Nithin the tube I is arranged loosely a metallic tube, K, the upper portion of which is screw-threaded, as shown at it, and is screwed through a corresponding hole formed at the middle of a metallic segment, L, which stands upon the upper head,f, of the magnet. The tube I is to be filled with mercury, as indicated at '1', Fig. 2, and as the tube K extends nearly its whole length into the mercury it will be seen that the tube I may rise and tall freely without breaking the electrical connection, which is maintained between the two tubes by the mercury.

The lower end of the tubular core G is provided with a collar, g, preferably of brass, and having opposite lateral extensions, g. (Shown clearly in the sectional view, Fig. 3.) Through the extensions 9 g are arranged adjustingscrews on. m, the lower ends of which are provided with shoulders m m, upon which rests an armature, M, conforming in external contour to the collar 9 and its extensions, the shanks of the screws m m passing loosely through apertures formed in the ends of this armature. The extensions 0 g of the collarg tut" are slotted, as shown at 9 Fig. 3, and the end portions of the armature M are similarly slotted, as shown at m M, Fig. 4. The armature M has a central aperture, through which the tube I passes loosely. In the slots of the armature are pivoted the bent levers N N, the upper vertical arms of which extend upward through the slots in the extensions 9 g of the collar, and carry at their upper ends the segmental armatures a a, which embrace without touching the opposite sides of the core G- justahove the collar g, so as to be attached directly by the core. The ends of the lower horizontal arms of the bent levers, which extend toward each other below the armature, terminate in rings 0 0, lapping each other, and loosely but rather closely surroundingthe tube I. From points near the upper ends of the vertical arms of the bent levers N N studs n a project outwardly, and have their outer ends secured to the tops of finger-springs a, the lower ends of which are firmly secured to the armature. These springs hold the upper arms of thelevers, and therefore thearmatures a or, away from the core G when the latter is not magnetized, the outward movement of the springs being limited by the outer end walls of the slots in the collar extensions, and the inward movement of the upper arms of the levers being limited by the inner end walls of said slots, so that the armatures will never touch the core. When the spring holds the armatures a a in their retracted position the lower arms of the levers will hold the rings 0 0 concentric, so that they will not touch the tube, which may then move up or down freely,- but when the armatures a n are attracted by the core G the lower arms of the lovers will move slightly outward, and the rings 0 0 will impinge with equal force upon opposite sides of the tube G, respectively, thus gripping or clutching said tube, and the armature M being at the same time attracted by the end of core Gr,said armature will carry upward the levers, which are attached to it, and also the tube 1, which is clutched by the rings 0 0 on said levers. It is this action which causes the carrier of the upper carbon, C, to separate it from the lower carbon, in order to establish the are.

The outer terminal of the coilfot' the magnet F is connected electrically with one end of the metallic segment I}, as shown at 1, Figs. 1 and 2, and the inner terminal, q, of said coil is passed through a passage made for itin the lower head,f of the magnet, and arranged across the tip of the clamping-screw h in a slight recess formed in the wall of the aperture, which embraces the metallic bar E, as shown in the sectional view, Fig. 2. This terminal can thus be forced into good electrical contact with the bar F.

From the positive binding-postpon the base A a stout gutta-percha covered copper wire, 1%, (shown in dotted lines, Fig. 1, and full lines in Fig. 2,) leads through suitable passage formed in the base A and the base b of the lower carbon'holdcr, and upward through the Edi hollow standard D and the vuleanite elbow (1, its upper extremity being bared, flattened, and coiled in a slight recess, as shown at s, in the top of elbow (I, so as to come into electrical contact with the end of bar E, through which electrical connection is made between the wire R and the coilfof the magnet. From the metallic base Z) of the carbon-holder B a wire, It, leads to the negative binding-post a, as shown in Fig. 1. The standards D and D are slotted vertically, as indicated in dotted lines, Fig. 1, to receive the straight shanks t t of curved metallic arms T T, which extend toward each other, and terminate on opposite sides of the carbon C withouttouchiug it, but within such distance of each other that the flange b of the upper-carbon holder B will lie upon the top of both arms and electrically connect them when said carbon-holder occupies its lowermost position. The arms T and T are pro vided with curved shoulders t t to bear against the inner surfaces of the standards D and D, and the shanks t and t, which project through the slots in the standards, are screw-threaded and provided with thumb'nuts, by which the shoulders t may be drawn firmly against the standards in order to hold the arms at any point to which they may be adjusted. The arm T is in direct electrical connection with the standard D; but the arm T is insulated from the standard D by means of vulcanitc in sulating-pieces t and t, Fig. (5, which are inserted in the slots in the standard, and have shoulders projecting laterally to insulate the shoulder t and the thumb-nut from the surface of the standard. The shank t passes through these insulating-pieces, and comes in contact with a bared portion, 'r, of the guttapercha covered wire R within the hollow stand ard. I preferably secure to the shank t a light metallic finger-spring, to press the bared portion of the wire closely to the shank, while still allowing the shank to slip in being adjusted.

The operation of my invention is as follows: The binding-posts p and n being connected to the line-wire, the current passes from the post 12 over the wire R, bar E, coil fof the magnet, metallic segment L, tube K, through the mercury in the tube I, through the tube I, carbonholder B, upper carbon, 0, lower carbon, C, lower-carbon holder B, the base I), and over the wire R to the binding-post n, and thence oft" to the line. In its first passage the current, in traversing the coil], magnetizes the core G, which simultaneously attracts the armature M and the segmental armatures n a, causing the tube 1 to be clutched and the upper carbon raised, as heretofore explained. The carbons being separated, the voltaie are will be established between them, and when by the consumption of the upper carbon the distance between the two and the length of the are increases, the increased resistance causes a diminution in the quantity of current traversing the coil], and consequently a decrease in the attractive force of the core G, so that IIO the armature M moves downward by gravity, and the armatures a n are retracted by their springs, thus releasing the tube I and allowing it to descend and carry downward the upper carbon until the shortening of the are so diminishes the resistance in the circuit that an increased quantity of current flows over the coil, the magnet is again strengthened, and attracts thearmatures,thus stoppingthedownward movement of the tube I and the carbon. In addition to its function of maintaining the circuit, the mercury by its weight insures the prompt falling of the upper-carbon holder when the resistance at the arc reaches a predetermined point. This extra weight is, however, easily raised by the magnet, owing to the low resistance and high inductive power ofits coil.

Owing to the large size of the wire of the coilf, it rapidly magnetizes the core G, when the full current flows, and by the simultaneous attraction and release of all the armatures by the same core an exceedingly sensitive arrangement is secured, which is affected by such slight variations of the current that no appreciable variation of the arc is produced, and consequently the light does not alternately increase and decrease in the manner so common in arc-lamps. When the current is not flowing of course the tube 1 falls freely, and the upper rests upon the lower carbon, so that although the clutch devices might not operate properly in any lamp the circuit would be kept closed and other lamps in the same circuit would not be interfered with.

Should the whole of the upper carbon be burned away or fall outof its holder, the tube I would drop until the flange b of the uppercarbon holder B would rest upon the tips of the arms T and T, and the current be shortcircuited from the magnet and upper structure of the lamp, a considerable resistance being thus removed from the circuit and waste of electricalenergy prevented. \Vhen the current is thus short-cirenited it flows from the bared portion 0' of the wire R to the shank tot the arm T and over said arm, carbon-holder I3 and T, standard D, base 11 and wire It to the binding-post a, and then otf to the line.

I am aware that in an electric-lamp regulator the movable core of an electro-magnet has been connected with a metallic rod which moves in a stationary body of mercury and maintains the circuit as the core moves and occupies different positions, and I do not claim such a device, broadly.

I am aware that in an arc-lamp a hollow helix in the main circuit has been provided with an auxiliary movable core arranged to lift a carbon pencil and having a clutchingarmature arranged for direct attraction by one end of said core; but the initial action of the clutching mechanism is feeble, and follows the initial movement of the core instead of being simultaneous therewith. I do not claim such a combination. Nor do I claim the combination of an electro-magnet having a stationary core and a carbon-lifting armature carrying supplementary clutch-operatin g armatures arranged for attraction by the said lifting-armature instead of by the magnet-core direct. The clutches being operated by a secondary magnetic induction are feeble in their action and lacking in promptness.

Having fully described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. In an electric-arc lamp, the combination of an eleetro-magnet having a stationary core and a helix of low resistance in the main circuit, a main carbon-lifting armature arranged for attraction by said stationary core, a clutching mechanism carried by said armature, and supplementary armatures arranged to be attached directly by the stationary core to operate the clutching mechanism simultaneously with the attraction of the main or lifting armature, substantially as described.

2. In an electric-arc lamp, a carbon-lifting magnet having a tubular core, a metal tube extending through said core and carrying acarbon-holder at its lower end, an armature provided with means for clutching said tube when attracted by the magnet, a conductor extending downward into said tube and connected with the main circuit and one terminal of the magnet-coil, the other terminal ofwhich is also connected to the main circuit, and a body of mercury within said metal tube and in contact with the conductor which extends therein, substantially as described.

3. The combination,with the magnet 1T, having the tubular core G, of the mercury-filled tube I, carrying the carbon-holder at its lower end, the armature M, carrying suitable devices for clutching and releasing said tube I, and the suitably-supported conductor K, extending into the said tube and the mercury there in, substantially as described.

4. The combination, with the core G of the carbon-controlling magnet, of a conductor carrying a carbon-holder, the armature M, and the clutch-levers pivoted to said armature, embracing said conductor at their lower ends, and carrying the armatures a a at their upper ends, substantially as described.

5. The combination,with the magnet F, having the tubular core G, of the tube I, tilled with mercury and carrying a carbon-holder at its lower end, the suitablysupported conductor K, extending into said tube and the mercury, the suitably-supported armature M, having a central'aperture for the passage of said tube I, and the bent levers N N, having the clutch-rings embracing said tube and carrying the retractible armatures a a, substantially as described. 1

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

GEORGE .l. MURDOCK.

\Vitnesses F. W. Downs, DAVID J. BARRY. 

